How Are Diamonds Formed? A Process More Complex than You Think

Most people who come across a beautiful, perfectly-shaped diamond ask themselves the same question: How are diamonds formed? While popular culture and media have painted a rather-simplistic picture of it, it has gotten it right when it comes to the two main forces that come into play during this process: Heat and pressure. However, the true process in which diamonds are formed is much more complex and difficult than many of us were led to believe. With that in mind, this brief article will go over the real process through which diamonds are formed.

A Brief History of Diamonds

batch of small diamonds

How are diamonds formed? In order to answer this question, it’s important to first provide some background regarding the history of diamonds.

The first documented unearthing of diamonds by humans happened in India in the 4th-century BC. Immediately, they were recognized as being valuable and dispersed along various ancient trade routes such as the Silk Road. Soon after, diamonds began being adopted by different groups, many of which claimed that the precious stones were gifts from the gods and brought health, wealth and strength.

It wasn’t long before their trade and use were spread to all the corners of the world. Today, diamonds continue to be extremely valuable, and they are still thought by many to hold energy or power.

How Are Diamonds Formed?

Essentially, diamonds are different forms of the element known as carbon. The formation of diamonds happens when pure carbon obtains a crystalline structure. This process is very rare. As a matter of fact, it takes place over thousands of years and under very particular conditions.

What Conditions Are Necessary for Diamonds to Be Formed?

Most of the diamonds that can be mined and gathered by men are formed in the earth’s mantle. The phenomenon occurs when concentrations of pure carbon known as graphite are subjected to pressure exceeding 725,000 pounds per square inch and temperatures above 2,000 degrees Fahrenheit. The combination of these two powerful forces modifies the graphite at an atomic level. It transforms its molecular composition from a hexagonal sheet pattern into a triangular shape. The result of that transformation is a diamond.

Diamonds that are created in the earth’s mantle are transported to the earth’s surface through volcanic pipes. These are underground volcanoes that go up to three times as deep as normal volcanoes. Full of magnesium and carbon dioxide, these volcanic pipes end up in eruption. This violent process elevates diamonds and other materials through kimberlite pipes. After the eruption, the diamonds are accummulated in pockets inside the earth, typically along precious and semi-precious gemstones like garnet and peridot.

Can Diamonds Form From Coal?

Diamonds and coal

While movies and popular belief may say otherwise, in short, the answer is no. However, it’s easy to see where the confusion lies: Both coal and graphite are made of carbon. At its core, the difference lies in the purity of their composition. While graphite is almost completely pure, coal has many other substances, including sulfur, hydrogen, mercury, oxygen, arsenic, nitrogen and selenium. Additionally, coal almost always contains a certain amount of organic materials (decaying plants, fungi or bacteria) and moisture. Because of these impurities, coal cannot transform into diamonds.

Going further than that, it can be said that most coal cannot possibly form diamonds. Coal is not subjected to the conditions necessary for that transformation to take place. As previously mentioned, carbon requires incredible amounts of both heat and pressure to change its atomic structure and become a diamond. Typically, coal is not found in locations that present those extreme conditions.

Other Ways Diamonds Can Be Formed

People who ask themselves the question of how are diamonds formed often wonder if there are different processes that can result in diamonds. Although most diamonds on earth are formed in the mantle, there are some that are formed under different conditions.

According to studies, many of the diamonds that can be found on surface-level deposits are the result of collisions between asteroids and the earth. Some of these collisions are as old as 35 million years old. While diamonds that were created in this way are not often of gemstone quality, they are strong and high-quality enough to be used for cutting and other industrial ends.

Amazingly, there are also diamonds that are not from this planet. To understand this, it is important to first know that carbon is the fourth most abundant element in the universe. Taking this into account, people who ask the question of how are diamonds formed can get a clearer vision of how this extraterrestrial diamonds can exist.

Apart from their origin, these diamonds are surprising due to their enormous size. These shockingly-big diamonds prompted scientists to come to a conclusion: They could only have been formed in a planet that was destroyed thousands (if not millions) of years ago in our solar system.

The Creation of Synthetic Diamonds

For millennia, people asked themselves the question of how are diamonds formed, often trying to replicate the process by themselves. However, that was not possible until, in the 20th century, mankind had made big-enough advancements in science to replicate the diamond formation process.

The first man-made diamond was created in 1954 by General Electric. This was achieved through the utilization of a process known as High Pressure High Temperature. By imitating the conditions in which diamonds are naturally formed, this process was able to produce real diamonds out of diamond seeds.

Later on, another process was developed for the creation of synthetic diamonds: Chemical Vapor Deposition. By superheating diamond seeds in plasma for around 28 days, scientists are able to create a perfect, cube-shaped diamond.

Wrapping Up

As it can be surmised by going through this article, the question of how are diamonds formed is not an easy one to answer. The processes through which diamonds are formed are incredibly complex, and they require incredible amounts of heat and pressure. Luckily, however, we live in a world where incredible materials such as diamonds are already in existence due to millions of years of geologic evolution.

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